Dilatation balloon catheters are known for use in valvuloplasty procedures, which are performed with respect to heart valves for purposes of dilatation to remove calcification and the like. Such catheters are also used to expand occluded arteries.
It is also known to emplace a catheter into its desired position in the heart by the procedure of float-advancement, in which a balloon is inflated near the distal tip of the catheter, after the catheter has been inserted into an appropriate blood vessel that leads toward the desired site of emplacement. Then, the inflated catheter balloon acts rather like a sail on a boat, being swept along by the stream of blood in the blood vessel, and thus carrying the catheter through the arteriovenous system of the patient into its desired position. When the desired position is reached, the balloon is deflated once again.
Thereafter, in the prior art a guidewire may be inserted through a separate catheter lumen which is open at both ends and extending through the catheter, for emplacement of the guidewire. Then, the float-advancement balloon catheter may be withdrawn, while leaving the guidewire in position, and a separate valvuloplasty catheter may be advanced along the guidewire into its desired position for the valvuloplasty procedure.
In the prior art it is often desired to insert a second valvuloplasty catheter through the same path within the arteriovenous system, so that its distal tip occupies a somewhat different location from the first catheter. For example, a pair of dilatation catheters may be provided in a valvuloplasty procedure to be positioned on opposite sides of a heart valve, for example the mitral valve. This has been accomplished up to the present time by repeating the process described above, using another float-advancement balloon catheter, followed by advancement of the guidewire through a lumen of the catheter once the balloon catheter has been properly positioned. Then, the float-advancement type balloon catheter may be removed, and a second valvuloplasty balloon catheter may be advanced along the second guidewire.
The above procedure exhibits the significant disadvantage that four catheters are required to obtain emplacement of two catheters in desired positions for a valvuloplasty procedure. Each of these catheters must be separately advanced into the patient, which increases the severity and challenge of the procedure.
In accordance with this invention, similar results may be obtained to the above procedure, with the elimination of one of the four catheters described above. Additionally, by this invention, easy monitoring of pressures on both sides of a heart valve may be obtained prior to advancement of the guidewires through the catheter.